A nitrile latex composition, nitrile gloves, and preparation methods and applications thereof

Abstract

The present invention belongs to the technical field of nitrile gloves, and discloses a nitrile latex composition, a nitrile glove, a preparation method and an application thereof. The nitrile latex composition of the present invention comprises the following components by weight: 100 parts of nitrile rubber latex, 1 to 3 parts of triazine-formaldehyde condensate resin, and 0.3 to 0.7 parts of vulcanizing agent. The nitrile gloves prepared from the nitrile latex composition of the present invention have a high elongation at break and a low modulus at a specified elongation, and the performance reaches or even exceeds the performance and feel of natural latex gloves; after the gloves are aged, the elongation at break and the modulus at a specified elongation change little; and they are very durable; and are suitable for the field of medical gloves.

Description

Technical Field

[0001] The present invention relates to the technical field of nitrile gloves, and in particular to a nitrile latex composition, nitrile gloves, and a preparation method and application thereof. Background Art

[0002] Disposable rubber gloves are widely used in medical examinations, health protection, the food industry, and other fields, offering convenience and disposable features. Medical gloves can be further categorized by material: latex gloves made primarily from natural rubber latex, nitrile gloves made primarily from nitrile rubber latex, and PVC gloves made primarily from polyvinyl chloride paste resin and plasticizers. Natural latex gloves have a softer feel and high elongation, but are not resistant to oils and organic solvents, contain proteins that can cause allergies, and are expensive, limiting their application. PVC gloves are cheaper, but have a harder feel and lower elongation, and their plasticizers are easily leached out by organic solvents, resulting in poor protective performance. Nitrile gloves are reasonably priced and offer far superior oil and solvent resistance to latex and PVC gloves, making them widely used. However, they have low elongation and are less durable. The ASTM standard for the physical properties of these three types of medical examination gloves is shown in Table 1. "After aging" refers to the accelerated aging process at 70°C for 168 hours, as specified in the standard.

[0003] Table 1 Standard ASTM D412

[0004] Physical property requirements for gloves Natural latex gloves Nitrile gloves PVC gloves Strength before aging (MPa) 18 14 7.5 Elongation at break before aging (%) 650 500 300 Strength after aging (MPa) 14 14 7.5 Elongation at break after aging (%) 500 400 300 Product requirements - US standard number ASTM D3578 ASTM D6319 ASTM D5250

[0005] Natural latex gloves also have a lower tensile stress than conventional nitrile and PVC gloves, resulting in a softer feel. For example, the 300% tensile stress of natural latex gloves is generally only 1-4 MPa, while that of conventional nitrile gloves reaches 6-15 MPa, and that of PVC gloves generally exceeds 7 MPa. Furthermore, the performance of both natural latex and nitrile gloves degrades with aging, particularly with elongation. This leads to a decrease in performance, elongation, and softness after long-distance transportation or storage.

[0006] Furthermore, existing nitrile gloves are not durable, especially when worn continuously for high elongation. For example, gloves with an elongation of 600% will typically break after no more than 60 minutes of continuous wear. Many gloves will develop cracks and holes after more than 90 minutes of continuous wear and normal use, particularly around the base of the thumb and between the fingers, areas subject to high stress during daily use. This not only requires frequent glove replacement, increasing costs, but also creates the potential risk of loss of protective effectiveness due to subtle, unnoticeable damage during use.

[0007] Therefore, it is urgent to develop a nitrile latex composition that can make gloves take into account elongation at break, modulus at a specified elongation and durability performance, so as to be applied to medical gloves. SUMMARY OF THE INVENTION

[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a nitrile latex composition, nitrile gloves, preparation methods and applications, so as to overcome the problem of difficulty in coordinating the strength, softness and durability of medical nitrile gloves in the prior art.

[0009] To achieve the above purpose, the technical solutions adopted by the present invention are as follows:

[0010] In the first aspect, the present invention provides a nitrile latex composition, which includes the following components by weight: 100 parts of nitrile rubber latex, 1-3 parts of triazine-formaldehyde condensate resin and 0.3-0.7 parts of vulcanizing agent;

[0011] The acrylonitrile content of the nitrile rubber latex is 28%-35%. Preferably, the acrylonitrile content is 29%-32% or 33%-34%.

[0012] In the nitrile latex composition of the present invention, the vulcanizing agent opens the unsaturated double bonds in the uncrosslinked linear polymer chains in the nitrile rubber latex with a specific acrylonitrile content and crosslinks them by bridging to form a network structure, which has high strength and elongation at break; the triazine-formaldehyde condensate resin in a specific proportion not only regulates the crosslinking degree of the vulcanizing agent to the nitrile rubber latex, but also crosslinks and fills the linear polymer of the nitrile rubber by itself, balancing the strength, elongation at break and modulus at a specified elongation of the crosslinked nitrile rubber latex, and improving the durability of the gloves. The prepared nitrile gloves are soft and comfortable to wear, and the feel is close to that of natural latex gloves; the modulus at a specified elongation and elongation at break are both close to those of natural latex gloves; the performance does not decrease significantly after aging, and the durability is good.

[0013] As a preferred embodiment of the nitrile latex composition of the present invention, the mass ratio of the triazine-formaldehyde condensate resin to the vulcanizing agent is 2-10:1.

[0014] As a preferred embodiment of the nitrile latex composition of the present invention, the vulcanizing agent is sulfur or tetramethylthiuram disulfide.

[0015] As a preferred embodiment of the nitrile latex composition of the present invention, it further includes at least one of an activator, an accelerator, an antioxidant, and a colorant.

[0016] Furthermore, by weight, it further includes 0-0.4 parts of activator, 0-0.7 parts of accelerator, 0-0.5 parts of antioxidant and 0-0.8 parts of pigment.

[0017] Furthermore, the active agent is a divalent metal oxide; preferably, the active agent is magnesium oxide or zinc oxide; the accelerator is a zinc salt of thiocarbamate or thiazole; preferably, the accelerator is at least one of accelerator ZDEC, accelerator ZDBC, and accelerator ZMBT; the antioxidant is at least one of phenolic, amine, phosphite, and hindered phenolic antioxidants.

[0018] In a second aspect, the present invention provides a nitrile glove made from the nitrile latex composition described above.

[0019] The nitrile glove of the present invention has a high elongation rate and a low modulus at a specified elongation, and its performance reaches or exceeds that of natural latex gloves in terms of performance and feel; moreover, the gloves are relatively durable; after aging, the elongation rate and modulus at a specified elongation of the gloves change little, indicating that even after long-term storage, the feel of the gloves still remains elastic and soft. Compared with conventional nitrile gloves, the elongation rate of the gloves is greatly increased, and the modulus at a specified elongation is significantly reduced.

[0020] In a third aspect, the present invention provides a method for preparing a nitrile glove, comprising the following steps:

[0021] (1) Take each component of the nitrile latex composition, mix them to obtain a premixed nitrile latex.

[0022] (2) Immerse the hand mold in a coagulant; then take out the hand mold and dry it.

[0023] (3) Immerse the hand mold in the obtained premixed nitrile latex, then take out the hand mold and dry it.

[0024] (4) Perform leaching treatment and dry vulcanization molding.

[0025] (5) After chlorination treatment, demold to obtain the finished product.

[0026] As a preferred embodiment of the method for preparing the nitrile glove, in step (2), the coagulant is calcium nitrate or calcium chloride.

[0027] In a fourth aspect, the present invention applies the nitrile latex composition, the nitrile glove, and the preparation method in medical gloves.

[0028] The nitrile glove of the present invention is close to natural latex gloves, softer, and comfortable to wear; it is very durable and can maintain continuous use for at least more than 2 hours without breakage; it is suitable for medical gloves.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] The nitrile gloves made from the nitrile latex composition of the present invention have high elongation and low tensile stress, achieving performance that matches or exceeds that of natural latex gloves in terms of both feel and feel, while also being softer and more comfortable to wear. The elongation and tensile stress of the gloves change little after aging, and the gloves maintain their elastic and soft feel even after long-term storage. Compared to conventional nitrile gloves, the gloves have significantly improved elongation and significantly reduced tensile stress. They are also extremely durable, capable of withstanding continuous use for at least two hours without breaking, making them suitable for use in the medical glove field. DETAILED DESCRIPTION

[0031] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] In the following examples and comparative examples, unless otherwise specified, the vulcanizing agent, activating agent, accelerator, antioxidant and pigment were all commercially available, and the same vulcanizing agent, activating agent, accelerator, antioxidant and pigment were used in the parallel experiments.

[0033] The raw materials used in the following examples and comparative examples are described below, but are not limited to these materials:

[0034] Nitrile rubber latex 1: model NL105, acrylonitrile content of 28%, purchased from Ningbo Yongxing Chemical Co., Ltd.

[0035] Nitrile rubber latex 2: model JZAH-3, acrylonitrile content of 35%, purchased from Dongying Jiuzhou Aohua Chemical Co., Ltd.

[0036] Nitrile rubber latex 3: model Nantex 640E, acrylonitrile content of 37%, purchased from Zhenjiang Nandi Chemical Co., Ltd.

[0037] Nitrile butadiene rubber latex 4: model Nantex 660, acrylonitrile content of 25%, purchased from Zhenjiang Nandi Chemical Co., Ltd.

[0038] Nitrile rubber latex 5: model X6617, acrylonitrile content 32%, purchased from Shanghai Xintema Chemical Co., Ltd.

[0039] Triazine-formaldehyde condensate resin: model BOC Sciences, purchased from BOCSCI Inc., USA;

[0040] Curing agent: sulfur, commercially available;

[0041] Active agent: magnesium oxide, commercially available;

[0042] Accelerator: Accelerator ZDEC, commercially available;

[0043] Antioxidant: Antioxidant 2246, commercially available;

[0044] Pigment: Titanium dioxide, commercially available.

[0045] The composition components of the nitrile latex compositions of Examples 1 to 10 and Comparative Examples 1 to 6 are shown in Table 2.

[0046] Table 2 Components of the nitrile latex composition (parts by weight)

[0047]

[0048]

[0049] Nitrile gloves were prepared respectively from the nitrile latex compositions of Examples 1 to 10 and Comparative Examples 1 to 6. The specific preparation steps are as follows:

[0050] (1) Take the components of the nitrile latex compositions of Examples 1 to 10 and Comparative Examples 1 to 6, mix them to obtain a premixed nitrile latex;

[0051] (2) Clean the hand mold and dry the moisture on the surface, then immerse it in the coagulant, and the coagulant is an aqueous solution of calcium nitrate; take out the hand mold and put it into the oven to dry the coagulant on the surface;

[0052] (3) Immerse the hand mold in the premixed nitrile latex, take out the hand mold and put it into the oven to dry;

[0053] (4) Leaching treatment, drying and vulcanizing and molding at a high temperature of 90 °C to 130 °C;

[0054] (5) After chlorination treatment, demold the glove to obtain the nitrile glove.

[0055] Detect the relevant properties of the nitrile gloves prepared respectively from the nitrile latex compositions of Examples 1 to 10 and Comparative Examples 1 to 6. The specific detection method is as follows:

[0056] (1) Adopt the standard "ASTM-D412 Test Method for Tensile Properties of Vulcanized Rubber and Thermoplastic Elastomers" to detect the relevant properties of the nitrile gloves prepared respectively from the nitrile latex compositions of Examples 1 to 10 and Comparative Examples 1 to 6, and after aging is after accelerating aging at 70 °C for 168 hours as specified in the standard.

[0057] (2) The detection method for durability is as follows:

[0058] Randomly select 10 staff members in the same position from the company's production workshop, including 5 males and 5 females. Before wearing the gloves, inflate and expand the gloves for inspection to ensure that there are no visually detectable holes or significantly thinner areas; then arrange for each staff member to wear gloves on both hands and perform daily work. The work content of the 10 staff members is the same; the tester visually inspects the gloves worn on the staff members' hands every 5 minutes to check for cracks, holes, and other damage. If damage occurs, stop wearing and record the puncture time; if the gloves remain intact after two hours, end the test. The tester records the puncture time of all gloves, and the result is the median of all gloves' puncture times. The longer the puncture time, the more durable the gloves.

[0059] The test results are shown in Table 3.

[0060] Table 3 Properties of Nitrile Gloves

[0061]

[0062] Continued Table 3 Properties of Nitrile Gloves

[0063] Performance Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Strength before aging (MPa) 9.6 21.2 18.3 7.2 20.1 23.9 Elongation at break before aging (%) 695.5 598.8 700.8 780.6 746.8 700.8 300% modulus at elongation before aging (MPa) 3.1 4.2 2.7 2.1 2.5 3.0 Strength after aging (MPa) 17.4 28.5 25.4 13.6 23.5 30.2 Elongation at break after aging (%) 598.3 527.2 698.9 761.8 741.2 576.4 300% modulus at elongation after aging (MPa) 3.9 4.8 2.8 2.6 2.9 4.2 Durability (continuous wearing duration) Burst after 20 minutes Burst after 25 minutes Burst after 25 minutes Greater than 2 hours Burst after 90 minutes Greater than 2 hours

[0064] The nitrile gloves prepared from the nitrile latex compositions of Examples 1 to 10 have high elongation at break and low modulus at a specified elongation, and their performance reaches or exceeds that of natural latex gloves in terms of performance and feel. The feel is softer, and they are comfortable to wear; moreover, the gloves are relatively durable; after aging, the elongation at break and modulus at a specified elongation change little, indicating that the gloves still maintain elasticity and softness even after long-term storage. Compared with conventional nitrile gloves, the elongation at break of the gloves is greatly improved, and the modulus at a specified elongation is significantly reduced.

[0065] Compared with Example 1, in the nitrile rubber latex compositions used in the nitrile gloves of Comparative Examples 1 and 2, the acrylonitrile content of the nitrile rubber latex was 37% and 25% respectively, and the properties of the two products showed polarization: the strength of the 37% content was unqualified, and the elongation at break was relatively high, while the strength of the 25% content was qualified, but the elongation at break was relatively low, and the durability of both gloves was poor; in the nitrile rubber latex composition used in the nitrile gloves of Comparative Example 3, no triazine-formaldehyde condensate resin was added. Although the properties before and after aging were acceptable and the gloves were relatively soft, due to the loss of the auxiliary cross-linking and filling effect of the resin, the elongation at break of the gloves was slightly low, and the gloves were very non-durable, and the continuous use time was short; in the nitrile rubber latex composition used in the nitrile gloves of Comparative Example 4, no vulcanizing agent was added. Although it had a relatively high elongation at break, a low modulus at a specified elongation, and good durability, the tensile strength was significantly low, less than 14 Mpa, not meeting the standard requirements; in the nitrile rubber latex composition used in the nitrile gloves of Comparative Example 5, the mass ratio of the triazine-formaldehyde condensate resin to the vulcanizing agent was 1:1. Due to the low usage amount of the resin, the other properties of the gloves were okay. However, although the durability was better than that of Comparative Example without resin at all, it was significantly inferior to that of the Comparative Example with normal usage amount; in the nitrile rubber latex composition used in the nitrile gloves of Comparative Example 6, the mass ratio of the triazine-formaldehyde condensate resin to the vulcanizing agent was 12.5:1. Due to the high usage amount of the resin, although the properties of the gloves were good before aging and they were relatively durable, the modulus at a specified elongation after aging was high, the elongation at break decreased greatly, and the soft touch of the gloves after aging decreased significantly.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A nitrile latex composition, characterized in that, By weight parts, it comprises the following components: 100 parts of nitrile rubber latex, 1 to 3 parts of triazine-formaldehyde condensate resin, and 0.3 to 0.7 parts of vulcanizing agent; the acrylonitrile content of the nitrile rubber latex is 28% to 35%; the mass ratio of the triazine-formaldehyde condensate resin to the vulcanizing agent is 2 to 10:1; the vulcanizing agent is sulfur or tetramethylthiuram disulfide.

2. The nitrile latex composition according to claim 1, wherein, It further comprises at least one of an activator, an accelerator, an antioxidant, and a colorant.

3. The nitrile latex composition according to claim 1, characterized in that, By weight parts, it further comprises 0 to 0.4 parts of activator, 0 to 0.7 parts of accelerator, 0 to 0.5 parts of antioxidant, and 0 to 0.8 parts of pigment.

4. The nitrile latex composition according to claim 2 or 3, characterized in that, The activator is a divalent metal oxide; the accelerator is a zinc salt of thiocarbamate or thiazole; the antioxidant is at least one of phenolic, amine, phosphite, and hindered phenolic antioxidants.

5. The nitrile latex composition according to claim 4, characterized in that, The activator is magnesium oxide or zinc oxide.

6. A nitrile glove, characterized in that, It is made of the nitrile latex composition according to any one of claims 1 to 5.

7. A preparation method of nitrile gloves, characterized in that, It comprises the following steps: (1) Take the components of the nitrile latex composition according to any one of claims 1 to 5, mix them to obtain a premixed nitrile latex. (2) Immerse the hand mold in a coagulant. Then take out the hand mold and dry it. (3) Immerse the hand mold in the obtained premixed nitrile latex, then take out the hand mold and dry it. (4) Perform leaching treatment, dry and vulcanize and mold. (5) After chlorination treatment, demold to obtain the finished product.

8. The preparation method of the nitrile gloves according to claim 7, characterized in that, In step (2), the coagulant is calcium nitrate or calcium chloride.

9. The application of the nitrile latex composition according to any one of claims 1 to 5, the nitrile gloves according to claim 6, and the preparation method according to claim 7 or 8 in medical gloves.

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